TABLE 5

Effects of cytoplasmic (cyto) or mitochondrial (mito 1 and 2) catalase overexpression in insulin-producing RINm5F cells on the cell death rate after exposure to IL-1β alone or a cytokine mixture

Cell clonesDestroyed cells (%)
IL-1βCytokine mixture
Control19 ± 3 (4)84 ± 3 (4)
Cyto10 ± 3 (4)*58 ± 3 (4)
Mito 18 ± 2 (4)*44 ± 3 (4)
Mito 24 ± 1 (4)§15 ± 2 (4)
  • Data are means ± SE (no. experiments). Insulin-producing RINm5F cell clones overexpressing catalase in the cyto and mito 1 and 2 and control cells were incubated for 72 h with IL-1β (600 units/ml) alone or with a cytokine mixture (60 units/ml IL-1β, 185 units/ml TNF-α, and 14 units/ml IFN-γ). Cell pellets were fixed for ultrastructural analyses. Destroyed cells in the sections were identified by electron microscopy, counted, and expressed as the percentage of the total number of cells. A total of 100–200 cells were analyzed in each section.

  • *

    * P < 0.05,

  • §

    § P < 0.01,

  • P < 0.001 vs. control cells;

  • P < 0.01 vs. mito 2 clone.